$-\dfrac{8}{12} + \dfrac{1}{5} = {?}$
Explanation: $ = - {\dfrac{8 \times 5}{12 \times 5}} + {\dfrac{1 \times 12}{5 \times 12}} $ $ = - {\dfrac{40}{60}} + {\dfrac{12}{60}} $ $ = - \dfrac{{40} + {12}}{60} $ $ = -\dfrac{28}{60}$